1. Field of the Invention
The invention relates to a material and methodology for the protection of the human head and body from soft tissue damage resulting from impulsive loading as a result of blunt object impacts. A particular aspect of the invention relates to a material and methodology for the reduction of head injuries during boxing, and to headgear and boxing gloves employing such material.
2. Discussion of Prior Art
The reduction of injury resulting from the effect of head and body impacts has been the subject of research for many years, particularly in the fields of automotive and military research. One commonplace strategy to mitigate the effect of impact on the body is to interpose a layer of protective material between the body and the source of impact. This is especially so in relation to head injuries, with head protection provided in the form of a helmet.
Protective materials have to date generally been developed with a view to minimising the gross displacement of the head or body produced by blunt object impacts. However, such a strategy takes no account of the often complex injury mechanisms within the body produced by the impact. Whilst there exists a fair degree of medical disagreement over precise injury mechanisms, it is clear that soft tissue injuries resulting from impact are due to a complex relationship between the type of impact and the nature of loads generated, the impact site and the material properties of the body at the impact site, degree of restraint on the body etc. For example, in the case of head impacts a number of possible injury mechanisms may be postulated and several of these are summarised below. Similar mechanisms can be postulated for damage to vital organs within the body cavity.
A severe blow to the head will cause the skull to accelerate rapidly, inertial effect will cause the brain to strike the accelerating skull with possibility of local injury. In addition, a blow to the head could result in a stress wave/pressure wave travelling through the brain. This wave would result in high, localised, shear stresses deep inside the brain leading to rupture of blood vessels. A stress wave travelling through the brain will undergo multiple reflections at the rear brain/skull interface, interference between waves could result in localised tensile stresses. These tensile stresses could, if high enough, tear brain tissue apart resulting in severe damage at the rear of the brain, remote from the point of impact. An impulsive shock is characterised by a broad continuous frequency spectrum and a further mode of damage may arise if specific frequencies cause the brain to resonate within the skull cavity leading to both localised and remote injuries. A blow to the head could also result in tri-axial forces producing both translation and rotation and as a result differential movement between the brain and brain stem could occur.